My gearbox grinds in third and fourth

Hi Hayward,

Yes. The clutch can cause an issue in just some gears or all. Normally as the clutch wears the gears that are used the most are the first to grind. Normally, this is first and second but there is no rule that says it can't be others.

Grinding is caused by really two main things. First, is a worn out clutch. Second are worn out synchronizer. The second is less common and should not be addressed until the clutch operation is tested and shown to be operating properly.

Here is a guide that explains this in a little more detail. However, it sounds like I would start with the clutch assembly and then retest. If the synchronizer is the issue you will need to open the transmission and disassemble the gears to replace this. Not entirely complicated but not an easy job either.

This sounds like the clutch disc is falling apart not allowing the clutch disc to spin "free" but to be sure let go over these videos and guide to help us fix the problem.

https://youtu.be/EpBMj5ZY_bo

and

https://youtu.be/JpzefqEeVGE

This guide can help as well

https://www.2carpros.com/articles/clutch-doesnt-work-sometimes-or-not-at-all

Please run down these guides and report back.